These Quick Fuel HR-series carburetors are packed full of the features that you'd expect from high performance carburetors. They are available in your choice of vacuum or mechanical secondary versions, and you can choose the cfm that's right for your specific engine combination. The Quick Fuel HR-series carburetors feature screw-in air bleeds, QuickSet sight windows in the fuel bowls, 4-corner idle circuits, screw-in idle restrictions, and a bright, shiny finish for durability.